v0.5.7

NetAudio 0.5.7 controls devices it used to refuse, installs on Alpine Linux, and makes routing presets work on DDM-managed devices.

Fixes:

• Devices that advertise a Dante protocol version NetAudio has no layout for, such as 2.8.10 through 2.8.14, can now be routed and configured. NetAudio uses the nearest known version at or below the one the device advertises. Before, every change to such a device was refused.
• netaudio installs with pip on Alpine Linux and other musl-based systems (#74).
• AES67 and lock changes are sent to DDM-enrolled devices instead of being withheld. A device that doesn't answer reports a timeout.
• Saving a routing preset no longer fails when a receive flow's details are incomplete, a channel isn't audio or has no label, or a channel reports both a Dante and an external subscription. The preset leaves out what it can't describe.
• A preset saved from several devices no longer fails because one of them can't be read, such as a device with no routing service. That device is left out and listed with the reason, and the rest are saved.
• A preset's audio and network sections no longer fail for a device because one of its settings can't be read, such as an encoding query that times out or an unknown interface addressing mode. That setting is left out and listed with the reason, and the device's other settings are saved.
• Routing presets work on DDM-managed devices. Routes from modern unicast receive flows are saved, subscription-created unicast flows are left out so loading no longer stalls, channels missing from a preset are unsubscribed, and loads use the logged-in DDM session.
• Preset XML carries each device's default name.
• Managed devices read their settings at startup and on refresh, keep showing readings after they age, enable the controls DDM permits, and show channel renames and other changes once they settle.
• A device shows as online only while it advertises a control service.
• A Shure receiver that is booting is retried for two minutes instead of being dropped.
• RTP receive flows and the native media mode are read back after changes.
• In the web app, the routing grid shows the hourglass from the click until the route is confirmed, row labels are no longer cut off, a renamed device's page follows the new name, and the latency table lists every device.

Thanks to stakach for #74.